Fifth Generation (5G) wireless communication systems (also referred to as new radio (NR) wireless communication systems) are purpose-built to support improved system performance. The 5G communication systems support a plurality of service types, a plurality of deployment scenarios, and wider spectrum ranges. The 5G wireless communication systems need to support different requirements from services of different service types. Therefore, resource scheduling in the 5G systems needs to have greater flexibility, and determination of a transport block size (TBS) in the resource scheduling needs to be more flexible.
In existing fourth generation (4G) Long Term Evolution (LTE) systems, for example, the determination of a TBS on a data channel of a terminal device includes the following steps:
Step 1: The terminal device determines a modulation scheme (modulation order) and a TBS index (I_TBS) according to a modulation and coding scheme (MCS) index (I_MCS) and an MCS mapping table predefined in a protocol.
Step 2: The terminal device determines, according to resource allocation information indicated by a network device, number of physical resource blocks (number of PRB, N_PRB) allocated in frequency domain.
Step 3: The terminal device searches in a predefined TBS table for a corresponding TBS value based on parameters such as the I_TBS and the N_PRB, to determine the TBS carried on the data channel.
In LTE systems, a basic assumption for determining the TBS is that a basic time unit for resource scheduling is one subframe (i.e. 14 orthogonal frequency division multiplexing (OFDM) symbols), and that number of resource elements available to the data channel in each PRB is fixed, for example, 120 resource elements (RE). However, for the 5G wireless communication systems, flexibility of resource scheduling increases greatly, and number of resource elements available to the data channel in each PRB varies greatly. In addition, scheduling time ranges and frequency domain ranges to be supported by the 5G wireless communication systems are extremely large. Therefore, if still using a manner of determining the TBS on the data channel in the LTE systems, operations would not be flexible, and scalability would be poor.